y=2x
When x increases by 3, y increases by...6 as y is equal to 2 times x.

y=3x+1
When x increases by 3, y increases by...surely you can work this one out now.
If you can't visualise these problems then just try out a few values to see the pattern.

4)
ySQUARED = 10

So:
yTO THE POWER OF 4 = 5
yTO THE POWER OF 20 = 1000

Take the square root of both sides of the equation y^2=10. Take the 4th root of the equation y^4=5. Take the 20th root of the equation y^20=1000. Compare your results, this will let you see if it is true or false. This method solves each equation to find y so that you can compare for consistancy.
Alternatively you could square the original equation and compare it to the next one. Also take the original equation and raise it to the tenth power and compare it to the third one. This method gives you the real values to compare to the given ones.

5) 2 to the power of 4 means 2*2*2*2. Similarly 2 to the power of 4 times 2 to the power of 4 means 2*2*2*2 times 2*2*2*2 or just 2*2*2*2*2*2*2*2 or 2 to the power of 8. I think from this example you should be able to answer the question now.